In the previous solutions, the subdistribution blocks are made of supports reached by lugs to be connected by the jumper cables. The conducting wires of the latter extend transversely through passages formed in the support in order to be fixed on each of the corresponding lugs. They are wound on said lugs and fixed by a nut screwed on the threaded end of the chosen lug.
But such solutions are not well adapted. Indeed, they are not easy to use. Each connection (a jumper cable includes at least two wires, which means that at least four lugs have to be connected two by two), makes it necessary to strip the end of a wire and to fix it to the associated lug. In addition, the connections thus made are generally made in the open-air and are subjected to working conditions which can cause an oxidation of the electric contacts due to the ambient moisture. This creates detremental shorts and generally spurious noise (crackling) on the lines.